Module 1: Cells as the Basis of Life Flashcards
What are prokaryotic cells?
Primitive, simple cells that do not have a nucleus
What are the four main structures in prokaryotic cells?
Cell membrane
Cytoplasm
Ribosomes
Genetic material
What is the cell membrane?
A structure that surrounds and encloses a cell
What is the cytoplasm?
The fluid part of the cells, outside of the nucleus that contains chemical substances
What are ribosomes?
Very small structures found in cytoplasm which manufacture proteins
What is genetic material?
DNA which contains all information of the cell.
What is the plasmid?
It is the circular ring of genetic material in prokaryotic cells
Which came first prokaryotic or eukaryotic cells?
Prokaryotic
What are the two main groups of prokaryotic cells?
Bacteria and archaea
What are eukaryotic cells?
Much more complex cells characterised by a membrane bound nucleus
What are ogranalls?
An internal structure of a cell enclosed by a membrane and has a function
What are organisms that contain eukaryotic cells known as?
Eukaryotes
What is the magnification of a light microscope?
x1500
What type of specimens can be viewed by light microscopes?
Living and non-living
What are two advantages of light microscopes?
Inexpensive and live specimens can be viewed
What is a disadvantage of light microscopes?
Can’t magnify more than 2000
What is a TEM?
Transmission Electron Microscope
How does a TEM work?
Electrons pass through the specimen
What type of image does a TEM produce?
2D
What is the most common type of electron microscope?
TEM
What are two advantages of TEM?
Offers the most powerful magnification and high quality images
What are two disadvantages of TEM?
Sensitive to vibration and electromagnetic fields and are hard to maintain
What is a SEM?
Scanning Electron Microscope
How does SEM work?
Bombards solid specimens with a beam of electrons which do not pass through but instead are scattered
What type of image does a SEM produce?
3D
What is an advantage of SEM?
Has the highest resolution and produces really good quality images
What are two disadvantages of SEM?
Very expensive and hard to maintain
What is the cell membrane?
A selectively permeable membrane around cells which controls intake of water and other chemicals
What is protoplasm?
It is the living content of a cell
What are the three things plant cells have that animal cells do not?
Cell wall
Chloroplasts
Large, permanent vacuole
What are the two things animal cells have that plant cells do not?
Centrioles
Lysosomes
What are the 8 things both animal and plant cells have?
Cell membrane
Cytoplasm
Cytoskeleton
Nucleus
Mitochondria
Endoplasmic reticulum
Golgi body
Ribosomes
What is the endoplasmic reticulum?
The network of flattened, interconnected membranes that provide transport
What is the difference between rough ER and smooth ER?
Rough have ribosomes attached whilst smooth do not
What does rough ER do?
Process protein made by the cell and synthesises lipids
What does smooth ER do?
It is the main site of lipid production
What are ribosomes and what do they do?
Small organelles made from RNA and protein which produce proteins
Where can ribosomes be found?
Free in the cytoplasm or on the surface of ER
What do golgi bodies do?
They process, package and sort cells
What are lysosomes?
Organelles which contain digestive enzymes which split complex chemical compound into simple ones
Where are lysosomes produced?
In the golgi body
What is the mitochondria?
The power house of the cell, producing energy in the form of ATP through the process of respiration
What type of membrane do mitochondria have?
Double membranes
What are cristae?
Fine folds of the inner membrane in mitochondria
What is the matrix?
Fluid in the central space of mitochondria
What is the vacuole?
A large fluid filled storage sac in the cytoplasm of a cell
What is the roll of the vacuole?
It provides support to plant cells
What are chloroplasts?
Organelles which are responsible for photosynthesis containing chlorophyll
What is chlorophyll?
Is the green pigment which traps sunlight that can then be used for photosynthesis
What type of membrane do chloroplasts have?
Double membrane
What is the stroma?
It is the liquid part of chloroplasts
What are thylakoids?
Stacks of membranes with chlorophyll on it
What are grana?
Stacks of thylakoids
What are cell walls?
Permeable structure which provides strength and support to plant cells
What are centrioles?
Form the spindles which hold chromosomes in a dividing cell
What is the cytoskeleton?
Framework which give cells shape and coherence
What is the fluid mosaic model?
Model of the structure of the cell membrane
What does the fluid mosaic model show?
Shows that the membrane is flexible and has a phospholipid bilayer
What forms the phospholipid bilayer?
Two layers of phospholipids
What is the structure of a phospholypid?
A head with two fatty acid chains
Which part of the phospholipid is hydrophilic?
The head
What does hydrophilic mean?
Able to absorb water or dissolve in it
Which part of the phospholipid is hydrophobic?
Fatty acid tails
What does hydrophobic mean?
Water avoiding or won’t dissolve in it
Which way are phospholipids positioned in the cell membrane?
Heads are positioned towards the outside and fatty tails face inwards
What are adhesion proteins?
Is a protein that links cells together
What are transport proteins?
Proteins which allow specific substances to move across the membrane
What are receptor proteins?
Proteins which bind hormones and other substances
What are recognition proteins?
Proteins which allow the body to recognise it as ‘self’
What are glycoproteins?
Marker proteins
What does permeability depend on?
Molecule size, electrical charge or lipid solubility
What molecules find it difficult to penetrate a membrane?
Water soluble molecules
What molecules can easily penetrate a membrane?
Lipid soluble molecules
What types of molecules are soluble in lipids?
Neutral molecules
What types of molecules are not soluble in lipids?
Charged molecules
How does water move through the membrane?
By a process called osmosis
What is diffusion?
It is the net movement of any molecule from high concentration to low until equilibrium is met
What is the only thing that can speed up diffusion?
Temperature
What is facilitated diffusion?
The process when channel proteins assist larger molecules in diffusing into cells
How do carrier proteins help with diffusion?
They bind to molecules, change shape and release the substance
How do channel protein help with diffusion?
Small ions can diffuse rapidly through them
What is osmosis?
The movement of water along the concentration gradient
What does hypotonic mean?
When the solution around the cells have lower concentrations
What does hypertonic mean?
When the solution around the cells have higher concentrations
What does turgid mean?
When a plant cell is full of water and no more can enter
What is the capsule?
Only found in bacteria and is a layer around it.
What is active transport?
Movement of molecules requiring the input of energy
Which way do molecules move during active transport?
Low concentration to high concentration
What is the concentration gradient?
Movement from high concentration to low
What is required for active transport?
Carrier proteins that spans the membranes
What is endocytosis?
Changing the shape of the cell membrane to surround a particle and engulf it
What is phagocytosis?
A type of endocytosis when a solid particle is engulfed
What is pinocytosis?
A type of endocytosis when fluid is engulfed
What is exocytosis?
Process by which substances are transported from inside a cell out
How does exocytosis happen?
A membrane bound vesicle moves to the cell membrane, fuses with it and then releases its content
How does SA:V affect cells?
It affects the movement of substances
What type of cells have high SA:V?
Smaller cells
What type of cells have lower SA:V?
Larger cells
What are inorganic nutrients?
Nutrients that do not contain carbon
What inorganic nutrients are required by cells?
Water, minerals, carbon dioxide (for photosynthesis) and oxygen
What are the four main organic compounds?
Carbohydrates, Lipids, Proteins and Nucleic Acids
What is the purpose carbohydrates?
It is a quick source of energy
What is the purpose of lipids?
Energy storage and form the structural component of membranes and hormones
What is the purpose of protein?
They form structural components in cells and tissues
What is the purpose of nucleic acids?
They are storage and expression of genomic information
What are carbohydrates made up of?
CHO
Carbon, hydrogen and oxygen
What are lipids made up of?
CHO
Carbon, hydrogen and oxygen
What are proteins made up of?
CHON
Carbon, hydrogen, oxygen and nitrogen
What is nucleic acid made up of?
CHONP
Carbon, hydrogen, oxygen, nitrogen and phosphorus
What are monosaccharides?
Simple sugars made up of from one sugar compound such as glucose
What are disaccharides?
Complex sugars made from 2 sugar compounds
What are polysaccharides?
Complex polymer sugars made from many sugars
What form are lipids most commonly found in?
Triglyceride
What are the building blocks of proteins?
Amino acids
What do amino acids form?
Peptides and polypeptides
What are the two types of nucleic acids?
RNA and DNA
What are enzymes?
They are biological catalysts which control all metabolic reactions in living cells
What are enzymes made from?
Protein molecules
What is the active site in an enzyme?
The surface of the enzyme with a specific shape
What are substrates?
The molecules which undergo chemical reaction on the active site of an enzyme
What is the Lock and Key Model?
Model of the enzyme where the active sight is rigid
What is the induced Fit Model?
It is the currently accepted version and is that the active sight is not rigid
How does temperature impact enzyme activity?
As temperature increases the rate of reaction also increases until optimal temperature
What happens if enzymes are exposed to very high temperatures?
They become denatured and can no longer be used
How does PH impact enzyme activity?
Each enzyme has its own narrow range of PH it can function in
What happens if enzymes are exposed to extreme PH levels?
They become denatured and can no longer be used
How does substrate concentration impact enzyme reactions?
Higher concentrations increases enzyme reactions until all enzymes are used / reaching saturation point
What is the word equation for photosynthesis?
carbon dioxide + water –> glucose + oxygen
What are the two stages of photosynthesis?
Light dependent stage (photolysis) and light independent (carbon fixation)
Where does the photolysis stage occur?
In the grana
What occurs during the photolysis stage?
Light energy is absorbed in the thylakoid membranes and water is split into H+ and 02 and ATP is formed
Where does the carbon fixation stage occur?
In the stroma
What happens in the carbon fixation stage?
CO2 and H+ combine to form glucose
When does anaerobic cellular respiration occur?
When there is a lacking amount of oxygen
What are the two common biochemical pathways in anaerobic cellular respiration?
Alcohol fermentation and lactic acid fermentation
What happens in alcohol fermentation?
Breakdown of glucose to form ethanol + CO2 + ATP
What happens in lactic acid fermentation?
Breakdown of glucose to form lactic acid + ATP
When does aerobic cellular respiration occur?
When there is a lot of oxygen available
What is the formula for aerobic cellular respiration?
glucose + oxygen –> carbon dioxide + ATP
